Lubricant and method of preparing same



Patented Aug. 13, 1940 UNITED STATES LUBRICANT AND METHOD- OF PREPARINGSAME I Lawrence M. Henderson, Winnctka, Ill., assignor to The Pure OilCompany, Chicago, IlL, a corporation of Ohio 2 No Drawing.

42 Claims.

lubricant is subjected in an automobile transmission or differentialisof essentially two kinds- 1) rubbing pressure and 2) rolling pressure.

Both actions are encountered during engagement of the gears combined invarying degrees.

Many testing machines have been developed to measure the ability of alubricant to stand up under extreme pressure conditiohs'such as areexperienced in connection with modern automotive gears. Of the numerousmachines perhaps the Floyd and the Timken are bestknow'n.

TheFloyd machine may be briefly described as follows: A' drive shaft isdriven by an electric motor. One end of the shaft is recessed to receiveacne-quarter inch diameter test shaft. Both shafts have holes drilledtherethrough adjacent contiguous ends to permit insertion of a brassshear pin. one-eighth inch in diameter. Theother end of the test shaftis mounted in a split bushing, the lower half of which is heldstationary. The bushing is one-half inch long and seven-eighths of aninch outside diameter.

A hydraulic press unit is positioned to exert pressure on'the upper halfof the bushing. The pressure can be varied at, will within certainlimits. 'A test box'encloses the bushing and the oil I to be tested isplaced in the box until the shaft is covered without submerging the. topbushing.

When the testis being made'the test shaft is rotated by themotor anddrive shaft and the pressure on the bushing is increased at definiteintervals. 'When the pressure exceeds the film strength of the oil, thetest shaft and bushing freeze together; causing the pin to shear.

' From data obtained on running thousands of. samples of normal minerallubricating oil which has not been especially treated for E. P.purposes, it has been found that these oils will not with- 50' standtwo" hundred poundsper'square inch hydraulic pressurefor five minutes.Oils that will withstand three hundred twenty five pounds per squareinch for five minutes are regarded as having extreme pressureproperties.

\ In order to calculate the actual load in pounds Application December19, 1935,

Serial No. 55,199

(Cl. 25248) l per square inch on the test specimens, the hydraulicpressure is multiplied by 76.97.

The oil to be tested can be heated to any desired temperature for thetest by means of electric resistance-element in the oil bath, controlledby a rheostat.

The Timken machine may be briefly described as follows: A one-quarterinch wide ring of carbon steel is fastened on a mandrel which is rotatedby an electric motor. A carbon steel block having a fiat surface isplaced directly beneath the ring and is adapted to be pressed upwardlyagainst the ring by a pivoted lever arm, on one end of which differentweights may be hung. The lubricant to be tested is made to flowcontinuously between the block and ring from a container adapted to beheated by an electric plate. After running the machine for a givenperiod, the test block is removed and the scar produced by the revolvingring, is measured. From the area of the scar the pressure which thelubricant was able to withstand can be calculated.

It frequently happens that a particular lubricant may appearsatisfactory when tested on the Timken machine and show poor E. P.characteristics when tested on the Floyd machine and vice versa. At thepresent time the Timken test is regarded with more favor than the Floydtest. The lubricants made in accordance with my invention exhibitexcellent E. P. characteristics when tested by either method.

One of the objects of my invention is to -pro-' vide a base materialwhich when added in suitable proportions to lubricating oils will impartthereto I E. P.- characteristics.

' Another object of my invention is to provide a lubricant having highE. P. characteristics.

A further object of my invention is to provide a method for preparing abase which will impart high E.-P characteristics to lubricating oils.

A still further object of my invention is to pro- .vide a good E. P.lubricant.

Other objects of my invention will be evident from the followingdetailed description of my process and products resulting therefrom.

To accomplish the foregoing objects, I sulfurize and phosphorize ananimal, vegetable, or marine oil preferably at elevated temperatures.-The oil is preferably one of relatively low unsaturation 'such as lardoil or cotton-seed oil, and is preferably sulfurized and thenphosphorized in two successive steps, but the two may be donesimultaneously. The sulfurization may be accomplished by using elementalsurfur or a sulfur compound such as sulfur chloride. Phosphorization ispreferably accomplished by means of a phosphorus compound such asphosphorus sesqui-sulfide or phosphorus tri-chloride, but elementalphosphorus as well as other phosphorus compounds may be used. The oil orfat to which a small percentage of sulfur or sulfur-compound is added,is heated for a period of time to chemically combine the sulfur with theoil. Phosphorus appears to have a marked tendency to polymerize theunsuliurized oil to a hard black product unless extreme care isexercised, and for that reason it is preferable to sulfurize first. Thesulfurized base is then mixed with a relatively small proportion ofphosphorus or phosphorus compound and the mixture heated untilcombination between the sulfurized base and the phosphorus takes place.

The resulting blend was tested on a Floyd machine and gave the followingresults:

Table 4 Gauge pressure at which pin sheared 475i! 425%! 50M 55M 5751?G00# 600% (10W 000! Temperature 109 109 120 121 131 202 200 22:1" 2:12lli v l 7156!! 7 32 8 50 812V! '37 8/50 8 50! 3'5 873] The resultingbase, when added in minor proportions to standard lubricating oil,produces a product having extremely high E. P. characteristics whenmeasured either on the Floyd or 'Iimken EXAMPLE II In another example,the base was prepared by mixing together the following ingredients:

machine. Table 5 EXAMPLE I Parts by weight As an example of an E. P.lubricant prepared s laljld on by simultaneously sulfurizing andphosphorizing i gg g an oil base, the following materials were mixedtogether Phosphorus pentsulfide .5 Table 1 Sulfur 9.5 Partsby weight andthe mixture heated for 2 hours at 425 F. No.1 lard oil 22.5 Theresulting material was cooled and blended Castor oil 22.5 with the samemineral oil given in the first ex- Linseed oil 45 ample, in theproportions of 15% of base to 7; Phosphorus pentsulfide 1 of mineraloil. This blend gave the following re- Suliur 9 suits on the Floydmachine:

Table 6 Gauge pressure at which pin sheared 525# 425# 450# No shear 475#5751! No shvor 50011 5003 Temperature... ll4 109 109 203 200 204 2352'11" 2310" Time 8'9 7'40 7'45 7'50" 3'32" 3'00" x0111" EXAMPLE III In athird example the following ingredients were mixed together and heatedat 425 F. for a the proportion of 15 parts by weight with 85 period of 3hours parts of Western Bright Stock having the follow- Table 7 ingcharacteristics: Parts by Weight No. 1 lard oil I 22.5 Castor oil 22.5Table 2 Rapeseed oil 45 Phosphorus trichloride 1 Gravity, A. P. I 2Sulfur 9 Flash. "F 530/540 Fire 0F 600/610 This base was blended withthe same mineral oil given in Example I, in the proportion of 15 partsVlscoslty at 210 155/165 of base to 85 parts of oil, and the followingre- Pour, F Ma-x 25 suits were obtained on the Floyd machine:

Table 8 Gauge pressure at which pin sheared. 5501 o00# 45011 firm 0001155011 00011 000: mm: Temperature 97 102 200 201 201 22% 227 Time 8'205'45" 1'41" m1" #44" 8'20 5'15 5'40" 5'10" sisting of 5 parts of GulfCoast lubricating oil When this base was blended with mineral oil in theproportion 10 parts of base to parts of oil, the following Floyd testswere obtained:

At this point the mixture was cooled rapidly to a temperature of 150 F.and then allowed to cool slowly to room temperature. The base thus pre-Table 9 Gauge pressure at whichpinshmirwl 5251! 375?! 42511 475# 575#600$! 600$ 'lcuiperalurc. 101 02 101 109 111 227 'liruc 8'10" 7113 732"7'52" 835" 8'50" 8'50" EXAMPLE 1V pared hada viscosity of from 400 to500 seconds As a fourth example, a base was prepared by mixing togetherthe following materials and heating them for a. period of 8 hours at 330to' This base was blended with the same mineral oil given in Example I,in the proportion of 10 parts of base to 90 parts of mineral oil. TheFloyd tests were as follows:

Table 11 at which pin I sheared, .\'n.\'lh:lr Noshmr, 2001; No shear Noshear ,'lciu u-nuurc 12;." 1113" 202 22 Time H 1'30" In the foregoingexamples the castor oil was used to lower the pour point of the base.The rapeseed oil was used to improve the miscibility of castor oil inmineral oil. and the lard oil, in addition to reacting with the sulfurand phosphorus to form the E. P. base material, was used to preventgel-formation which is obtained when castor and rapeseed oils are heatedalone.

The following description is an example of a preferred method forpreparing sulfurized and phosphorized base but is in no way intended tolimit the invention to the particular conditions, constituents, or thequantities of the various constituents stated.

To 87.1 parts by weight of prime lard oil was added a homogeneousmixture or solution conof 200 to 210 Saybolt Universalviscosity at 100F.

and 43 to 15 Saybolt Universal viscosity at 210 F.

and 0.5 of a part of sulfur chloride, and the entire mixture wasvigorously agitated. The mixture was then slosaly heated to atemperature of 270 F. while being agitated, and then 7.4 parts of finelydivided flowers of sulfur were added. The addition of the flowers ofsulfur took place over a period of about 10 minutes and the temperatureof the mixture was maintained at approximately 270 to 280' F. a

After addition of the flowers of sulfur, the temperature of the mixturewas raised to 330 F. and agitated for a period, of approximately '7hours while the temperature was maintained at from 330 to 340- F.Corrosion tests of the mixture were made from time to time by immersinga polished copper strip therein for 2 minutes. At

is satisfactory.

Saybolt Universal at 210 F.

The sulfurized base was then phosphorized by adding thereto an amount offinely divided phosphorus sesqui-sulfide ranging from 0.1 to 2% of thesulfurized base. The mixture was cooked for 1 hour at a temperature ofapproximately 280 F. and then allowed to cool to atmospherictemperature.

A series of tests on the Timken machine were run on lubricating oils towhich were added sulfurized and phosphorized lard oil base prepared inthe manner just described. Various amounts of sulfur and phosphorussesqui-sulfide were used in preparing the base. The table given belowsets forth the results obtained. The blends were made by adding 18% byvolume of the sulfurized and phosphorized base to a Gulf Coastlubricating oil blend having the following specifications: ViscositySaybolt Universal at 130 F., 1100-1215; viscosity Saybolt Universal at210 R, 160-170; pour F. (maximum), +15 F.

Table 12 Percent Percent 12 Viscosity of Timkon test sulfur 331 5resulting pressure base added to base at 210 F1 lbsJsq. in.

base

It will be apparent from the above table that insofar as the E. 1?.characteristics of the lubricant are concerned, there is no advantage inincreasing the sulfur content of the base in excess of approximately 5%since the base having 5% of sulfur showed a better Timken test than thebase having 9% of sulfur: Likewise, it will be apparent that generallyspeaking, an increase in phosphorus sesqui-sulfide increases the Timkentest and that the optimum amount of phosphorus sesqui-sulfide liessomewhere between 0.2 and 2% since the Timken test increases rapidly upto 0.2% whereas increase from 0.2 to 2% is comparatively small.

In preparing the bases listed in the above table, heavy white phosphorusfumes were given off during phosphorization, indicating loss of somephosphorus. This loss accounts for the fact that the Tirnken tests inthe table are somewhat erratic.

A number of Timken tests were also made on lubricants representingvarious combinations of the oils and reagents used in preparing thesulfurized and phosphorized lubricant in order to compare the E. P.characteristics thereof with those of the finished sulfurized andphosphorlzed base lubricant. The results of these tests are given in thefollowing table:

Table 13 1 Flo d test g gg test gauge pres- 8 re, Sum 1 lbs/sq. in.

Gulf coast lub. oi]. (same as used in 8,900 150 194 1 Table 12) u, 100150 225: F Lub. oil 18% prime lard oil 13,230 132g 22., f Lub. oil 18%sulfurized prime lard 12,950 375 199 F oil. (sulfurized as in example)15,600 350 223 F Lullil. oiizld+ l8? Bigg e lrardh oil 11])!108- 250 F por wit 0. o p osp orus ses'qui-suliide 550 F Lub. oll blend with 0.4%phosphorus 16, 250 175 193 F. L l o i l -i l a li a" 'i 'rli 750 125 225u .o su uriz p rmea 30500 550199F oil and phosphonzed with 0.4 aI"Ell;05131210111Szl llCll}(t)l'ld:e.d .1 750 500 230 o 18,4, su uriprime an 000 (a) F oil pbosphorized with 0.4 phos- I o phorusscsqui-sulflde. 000 000 (a) 229 It is evident from a comparison of thetests on the blends shown above that those made from a sulfurized andphosphorized base are far superior to the other and are the only blendswhich give satisfactory tests on both the Timken and the Floyd machines.

Although I have disclosed the use of lard oil in the preparation of thebase, it will be understood that other fatty oils, vegetable. animal, ormarine oils and waxes, such as rapeseed, cotton and sperm oil, may besubstituted therefor, or a mixture of the various oils may be used. Oilsof lower unsaturation are preferable to oils of high unsaturat'ion suchas linseed and tung oils since the latter appear to polymerize in use.

The proportions of the various constituents entering into the finishedproduct may vary over wide limits but it is preferable to keep thesulfur in the base below 10% and the phosphorus below 2%. In place ofphosphorus sesqui-sulflde; other phosphorus compounds may be used inpreparing the base, such as phosphorus trichloride, phosphoruspentoxide, various phosphides, such as tin phosphide, and in general,elemental phosphorus and bi-elemental phosphorus compounds. Theproportion of the base to oil with which it is blended may also varyover wide limits depending upon the viscosity, pour point, and the E. P.characteristics ofthe finished product desired.

It will be understood that my invention is not limited to any specificconditions of temperature at which the base is prepared but that anysuitable temperature at which the sulfur and phosphorus are effectivelycombined with the oil base, may be used.

What I claim is:

l. The method of preparing lubricating stock which comprises sulfurizingfatty material and then phosphorizing the sulfurized material.

2. The method of preparing lubricating stock which comprises sulfurizingfatty oil and then phosphorizing the sulfurized oil.

3. The method of preparing lubricating stock which comprises chemicallycombining a relatively small amount of sulfui with a fatty oil and thenchemically combining a small amount of phosphorus with the sulfurizedoil.

4. The method of preparing an extreme pressure lubricating base whichcomprises mixing a relatively small amount of sulfur with a nondrying orsemi-drying fatty body, heating the mixture until the sulfur chemicallycombines with the fatty body, mixing a small amount of phosphoruscompound with the sulfurized body and mildly heating the mixture untilthe phosphorus has entered into chemical combination.

5. The method of preparing an extreme pressure lubricant base whichcomprises mixing lard oil with sulfur chloride and sulfur, heating themixture until chemical combination between the sulfur and oil takesplace, adding a small amount of phosphorus sesqui-sulfide to thesulfurized oil and heating the mixture for a suflicient period of timeto cause the phosphorus to chemically unite with the sulfurized base.

6. The method of preparing an extreme pressure lubricant base whichcomprises admixing sulfur chloride with a small amount of minerallubricating oil, adding the mixture to a relatively large quantity oflard oil, heating the mixture with vigorous agitation to a temperatureabove the melting point of sulfur, adding sulfur to the mixture andheating the mixture to a temperature at which the sulfur combineschemically with the oil, then adding phosphorus sesqui-sulfide to theoil and agitating at sufficient temperature to chemically combine thephosphorus with the sulfurized base.

'7. Method in accordance with claim 4 in which an amount of sulfur up to10% by weight of the fatty body and an amount of phosphorus compoundcontaining from .1 to 2% of phosphorus by weight of the sulfurized bodyare used.

8. Method in accordance with claim 5 in which the total sulfur mixedwith the lard oil is not in excess of 10% of the lard oil and thephosphorus content of the phosphorus sesqui-sulflde ranges from .1 to 2%by weight of the sulfurized oil.

9. Method in accordance with claim 6 in which the sulfur content of thesulfur chloride does not exceed 10% by weight of the oils and thephosphorus content of the phosphorus sesqui-sulflde ranges from .1 to 2%by weight of the sulfurized oil.

10. The method of preparing an extreme pressure lubricating base whichcomprises mixing a small quantity of phosphorus compound selected fromthe group consisting of the chlorides and sulfides of phosphorus with asulfurized fatty oil, heating the mixture to a temperature up toapproximately 280 F. in order to cause the phosphorus to combine withthe sulfurized fatty oil, continuing the heating until the phosphoruscompound has reacted with the sulfurized oil, and then cooling theresulting product.

11. The method of preparing an extreme pressure lubricating base whichcomprises sulfurizing fatty oil by heating a small quantity of sulfurand sulfur chloride with mineral oil and the fatty oil up to atemperature of approximately 330 F. until the resulting product showssubstantially no corrosion to a copper strip, then adding a small amountof a phosphorus compound selected from the group consisting of sulfidesand chlorides of phosphorus and heating the mixture to a temperature upto approximately 280 F. in order to cause the phosphorus to react withthe sulfurized oil, and cooling the resulting product.

12. Method according to claim 10 in which the phosphorus compound isphosphorus sesqui-sulfide and it is added in amounts of .1 to 2% of thesulfurized material.

13. Method according to claim 11 in which the phosphorus compound isphosphorus sesqui-sultide and it is added in amounts of .1 to 2% of thesulfurized material.

14. Method in accordance with claim 16 in which the sulfurized fatty oilis prepared by heating the fatty oil with a small amount of sulfur andsulfur chloride to a temperature up to approximately 340 F. until thesulfur has reacted with the fatty oil and the resulting productshowssubstantially no corrosion to a copper strip.

15. The method of making an extreme pressure lubricating stock whichcomprises sulfuriz ing fatty oil and then chemically reacting abielemental phosphorus compound with the sulfurized oil. I f a 16.Method according to claim 15 in which the phosphorus compound is a metalphosphide.

17. Method according to claim 15 in which the oil .is sulfurized byheating it with a small quantity of sulfur and sulfur chloride to atemperature sufficient to cause the sulfur to chemically unite with theoil.

18. Method according to claim 15 in which the phosphorus compound is asulfide of phosphorus.

19. The method of preparing lubricating stock which comprises chemicallycombining fatty material with sulfur and phosphorus in such proportionsthat the ratio of combined sulfur to combined phosphorus is greater thanthe ratio of sulfur to phosphorus in phosphorus pentasulfide, andretaining the sulfur and phosphorus in chemical combination with thefatty material..

20. Method in accordance with claim 19 in which the fatty material isfatty oil.

21. The method of preparing lubricating stock which comprises chemicallycombining fatty material with sulfur and phosphorus, said sulfur beingobtained from the group consisting of elementarysulfur and sulfurhalides and retaining sulfur and phosphorus in chemical combination withthe fatty material.

22. Method in accordance with claim 21 in which sulfur is obtained fromthe group consisting of elementary sulfur and sulfur chlorides.

23. Method in accordance with claim 21 in which the fatty material isfattyoil.

24. Method inaccordance with claim 21 in which the sulfur is obtainedfrom elementary sulfur. v

25. Method in' accordance with claim 21 in which the sulfur is obtainedfrom sulfur monochloride.

26. The method of preparing lubricating stock which comprises chemicallycombining fatty material with sulfur and phosphorus, said sulfur beingobtained from the group consisting of elementary sulfur and sulfurhalides and said phos-' phorus from the group consisting of elementaryphosphorus, phosphorus sulfide. phosphorus 28. Method in accordance withclaim 26 in which the combined sulfur is obtained from elementarysulfur.

29. Method in accordance with claim 26 in which the combined sulfur isobtained fromsul fur monochloride.

30. Method in accordance with. claim 26 in which the combined phosphorusis obtained from phosphorus sulfide.

31. Method in accordance with claim 26 in which the combined phosphorusis obtained from phosphorus sequisulflde.

32. A lubricating stock comprising fatty material in chemicalcombination with sulfur and phosphorus, said sulfur being obtained fromthe group consisting of elementary 51111111 and sulfur halides.

33. A lubricating stock in accordance with claim 32 in which the sulfuris obtained from the group elementary sulfur and sulfur chlorides.

34. A lubricating stock in accordance with claim 32 in which the sulfuris obtained from elementary sulfur.

35. A lubricating stock in accordance with claim 32 in which the fattymaterial is fatty oil.

36. A lubricating. stock in accordance with claim 32 in which the fattymaterial is lard oil. 3'7. A lubricating stock comprising a majorportion of mineral lubricating oil and a minor portion of fatty oil,said fatty oil being in chemical combination with sulfur and phosphorus,said sulfur being obtained from the group consisting of elementarysulfur and sulfur halides.

38. A lubricating stock in accordance with claim 37 in which the sulfuris obtained from the group consisting of elementary sulfur and sulfurmonochloride.

39. A lubricating stock comprising fatty oil in chemical combinationwith sulfur and phosphorus in such proportions that the ratio ofcombined sulfur to combined phosphorus is.

greater than the ratio of sulfur to phosphorus in phosphoruspentasulfide. v

40. A lubricating stock in accordance with claim 39 in which the sulfurdoes not exceed and the phosphorus does not exceed 2%.

41. An extreme pressure lubricant comprising a major portion of minerallubricating oil and a minor portion of fatty oil in chemical combinationwith sulfur and phosphorus in such proportions that the ratio ofcombined sulfur to combined phosphorus is greater than the ratio ofsulfur to phosphorus in phosphorus pentasulfide.

42. A lubricating stock in accordance with claim 41 in which the sulfurdoes not exceed 10% and the phosphorus does not exceed 2%.

LAWRENCE M. HENDERSON.

